Teo Ghim Heng v Public Prosecutor [2022] SGCA 10

Case Details

• Citation: [2022] SGCA 10
• Title: Teo Ghim Heng v Public Prosecutor
• Court: Court of Appeal of the Republic of Singapore
• Case Number: Criminal Appeal No 36 of 2020
• Date of Decision: 23 February 2022
• Date Judgment Reserved: 13 October 2021
• Judges: Sundaresh Menon CJ, Judith Prakash JCA, Steven Chong JCA, Belinda Ang Saw Ean JAD, Chao Hick Tin SJ
• Appellant: Teo Ghim Heng
• Respondent: Public Prosecutor
• Legal Areas: Criminal Law — Offences, Constitutional Law — Attorney-General, Constitutional Law — Equality before the law
• Statutes Referenced: Penal Code (Cap 224, 2008 Rev Ed) (“PC”) — ss 299 and 300(a); s 300(a) murder; s 300 murder exceptions (Exception 1 and Exception 7); s 300(a) charge; s 300 generally; s 299 (culpable homicide)
• Constitution Referenced: Constitution of the Republic of Singapore (1985 Rev Ed, 1999 Reprint) — Art 12(1)
• Lower Court Decision: Public Prosecutor v Teo Ghim Heng (Zhang Jinxing) [2021] SGHC 13
• Judgment Length: 60 pages, 16,673 words
• Core Issues on Appeal: Whether the defences of diminished responsibility (Exception 7) and grave and sudden provocation (Exception 1) were made out; and whether ss 299 and 300(a) of the Penal Code were unconstitutional (separation of powers and Art 12 equality)

Summary

In Teo Ghim Heng v Public Prosecutor ([2022] SGCA 10), the Court of Appeal dismissed a criminal appeal against convictions for two counts of murder under s 300(a) of the Penal Code. The appellant, Teo Ghim Heng, accepted that the elements of murder were satisfied, but sought to rely on two statutory exceptions to murder: Exception 7 (diminished responsibility) and Exception 1 (grave and sudden provocation). The trial judge rejected both defences, and the Court of Appeal upheld that decision.

The case is also notable for the appellant’s constitutional challenge to the statutory provisions under which he was charged, namely ss 299 and 300(a) of the Penal Code. He argued that these provisions violated the separation of powers doctrine and contravened Art 12(1) of the Constitution (equality before the law). The Court of Appeal rejected these arguments as legally unsustainable, affirming the constitutionality of the relevant murder framework.

What Were the Facts of This Case?

The facts, as far as they were material to the appeal, were largely undisputed and were set out in detail in the High Court’s decision in Public Prosecutor v Teo Ghim Heng (Zhang Jinxing) [2021] SGHC 13. The Court of Appeal emphasised that the account of the crimes and the appellant’s motivations came largely from the appellant himself, because there were no witnesses to what happened inside the family flat.

At the time of the offences, the appellant was the sole breadwinner of his family. Before 2015, he had worked as a property agent and earned a five-figure monthly income. From 2015 onwards, a downturn in the property market reduced his income significantly. Despite this, his family’s expenses remained high, and he continued to spend several hundred dollars per week on gambling. As a result, he depleted his savings and accumulated substantial debts, borrowing from friends, colleagues, and financial institutions. By the end of 2016, he owed at least $120,000.

In October 2016, the appellant joined an interior design firm, Carpentry Design Works Pte Ltd (“CDW”), as a sales coordinator under the supervision of Mr Lim Zi Jian (“Mr Lim”), earning about $1,500 per month, while continuing part-time property work. Even with these efforts, he continued to accumulate debts. The financial pressure formed the backdrop to the events of January 2017.

On 19 January 2017, the principal of the playschool attended by the appellant’s daughter, Teo Zi Ning (“Zi Ning”), sent the appellant a text message requesting payment of overdue school fees of $1,700. The appellant felt vexed because he did not have the ability to pay. The next morning, while the appellant, his wife Choong Pei Shan (“Pei Shan”), and Zi Ning were in the master bedroom of their flat (“the Flat”), the appellant told Pei Shan that he did not wish to send Zi Ning to school that day because the school fees were overdue and he feared Zi Ning might be asked to leave, which would be “very embarrassing”. Pei Shan became enraged, berating him as a “useless” father and husband.

The appellant claimed that, upon hearing these words, his mind became a “complete blank”. He then retrieved a bath towel, looped it around Pei Shan’s neck, and pulled tightly to strangle her. After about five minutes, he said his mind cleared, but he continued strangling her. He stated that he intended to kill his entire family and then commit suicide because he believed there was no way for the family to repay the debts. After about 15 minutes, he let go of the towel and strangled Pei Shan with his bare hands until she stopped breathing completely. At the time of her death, Pei Shan was pregnant with the appellant’s second child.

After killing Pei Shan, the appellant considered killing Zi Ning as well. He reasoned that if Pei Shan and the appellant were gone, Zi Ning would not have anyone to care for her, and he did not want her to suffer the consequences of the debts. He asked Zi Ning to sit down in front of him with her back facing him, looped the same bath towel around her neck, and pulled both ends to strangle her. After about 10 to 15 minutes, he released the towel and strangled Zi Ning with his bare hands until she stopped breathing completely.

Immediately after the killings and in the days that followed, the appellant contemplated or attempted suicide multiple times. These included attempts by slitting his wrists with a penknife, overdosing on Panadol, attempting to purchase rat poison, planning to jump to his death, attempting again with Panadol, attempting to slit his wrist again, spraying insecticide and drinking it, and planning to burn the bodies and immolate himself (which he abandoned because he found the heat “unbearable”). He also planned to drown himself at Sembawang Park but did not carry it out.

In addition, the appellant took steps to avoid contact with others who might search for him or his family. He switched off his handphone and used Pei Shan’s handphone so that creditors could not contact him, informed Zi Ning’s teacher that Zi Ning could not attend school because she was not feeling well, made excuses for family dinners, pretended he was not at home when colleagues visited, and accessed Pei Shan’s Facebook to change her cover photo to give the impression she was active online. Between the killings and his arrest, he spent time watching television and YouTube, playing games, consuming pornography, searching online for methods of committing suicide, and smoking in the study.

Pei Shan’s and Zi Ning’s deaths were discovered on the evening of 28 January 2017. Pei Shan’s brother, Mr Choong, and Mr Choong’s brother-in-law visited the Flat and noticed a pungent odour coming from the windows. Mr Choong called the police, and the appellant was arrested shortly thereafter. He was charged with two counts of murder under s 300(a) of the Penal Code.

What Were the Key Legal Issues?

Two statutory exceptions to murder were central to the appeal. First, the appellant argued that he should be convicted of a lesser offence or that the murder charge should not stand because Exception 7 (diminished responsibility) applied. He contended that he was suffering from an abnormality of mind arising from moderate Major Depressive Disorder (“MDD”) which substantially impaired his responsibility for the killings of Pei Shan and Zi Ning.

Second, the appellant relied on Exception 1 (grave and sudden provocation). He argued that he lost self-control as a result of words uttered by Pei Shan immediately before he killed her and Zi Ning. The legal question was whether the provocation was “grave” and “sudden” in the relevant sense, and whether it was sufficient to support the statutory exception given the appellant’s conduct before and during the killings.

Beyond the statutory exceptions, the appellant mounted a constitutional challenge. He argued that ss 299 and 300(a) of the Penal Code were unconstitutional because they offended the separation of powers doctrine by permitting the Prosecution to encroach into the judiciary’s sentencing powers, and because they were inconsistent with Art 12(1) of the Constitution (equality before the law). The Court of Appeal had to determine whether these constitutional arguments were legally sustainable.

How Did the Court Analyse the Issues?

The Court of Appeal began by noting that the elements of murder under s 300(a) were accepted as satisfied. The appeal therefore turned on whether the appellant could bring himself within the statutory exceptions and whether his constitutional objections could affect the validity of the charges.

On diminished responsibility (Exception 7), the Court of Appeal agreed with the High Court’s approach. The trial judge treated the primary issue as whether the appellant had been suffering from moderate MDD at the material time. While diminished responsibility is often supported by expert psychiatric evidence, the Court of Appeal endorsed the principle that the court is not bound to accept expert conclusions if the factual foundation (“bedrock of facts”) is not properly established. In other words, the court may evaluate whether the objective evidence supports the symptoms and history relied upon by the expert.

The Court of Appeal highlighted that the appellant’s own account and conduct contained features inconsistent with the claimed psychiatric impairment. The trial judge had observed “clear and dishonest thinking” on several occasions, and this mattered because it suggested a level of cognitive functioning and intentionality inconsistent with a substantial impairment of responsibility. The Court of Appeal accepted that, in assessing symptoms, the court should approach self-reported symptoms cautiously and, as far as possible, seek support in objective evidence. This is a practical evidential point: where the defence relies heavily on the accused’s narrative of mental state, the court will scrutinise whether that narrative is corroborated by conduct and other evidence.

On provocation (Exception 1), the Court of Appeal focused on both the nature of the alleged provocation and the appellant’s reaction. The alleged provocation was Pei Shan’s berating words calling him “useless” and related remarks. The Court of Appeal agreed that, on the facts, the provocation was neither grave nor sudden in the legally relevant sense. The statutory exception is not triggered by any insult or anger; it requires a specific kind of triggering event and a loss of self-control that is temporally and causally connected to the provocation.

More importantly, the appellant’s manner of killing and the sequence of events undermined the claim of loss of self-control. The Court of Appeal considered the appellant’s conduct before the killings, including his earlier decision to keep Zi Ning from school due to overdue fees and the subsequent escalation. It also considered the appellant’s actions during and after the killings, including the planning-like elements and the steps taken to conceal his whereabouts and avoid detection. These actions were inconsistent with the narrative that the appellant acted purely under the immediate impulse of sudden provocation.

In relation to the constitutional challenge, the Court of Appeal rejected the appellant’s arguments. While the extract provided does not include the full reasoning, the Court of Appeal’s conclusion was that the separation of powers and Art 12(1) arguments were not legally sustainable. The court therefore treated the constitutional challenge as failing at the threshold, without requiring any alteration to the statutory framework governing murder and its exceptions.

From a doctrinal perspective, the Court of Appeal’s handling of the constitutional issues reflects a common judicial approach: constitutional challenges to criminal statutes are assessed with care, and where the arguments are framed in a manner that does not engage the legal requirements for a constitutional breach, the court will dismiss them. Here, the court affirmed that the Penal Code provisions under which the appellant was charged remained valid and enforceable.

What Was the Outcome?

The Court of Appeal dismissed the appeal and upheld the High Court’s convictions for two counts of murder under s 300(a) of the Penal Code. The Court of Appeal agreed that the appellant had not made out either Exception 7 (diminished responsibility) or Exception 1 (grave and sudden provocation).

The Court of Appeal also rejected the appellant’s constitutional challenge to ss 299 and 300(a) of the Penal Code on separation of powers and Art 12(1) grounds. The practical effect is that the murder convictions stood, and the statutory defences and constitutional arguments did not provide any basis for overturning the convictions.

Why Does This Case Matter?

Teo Ghim Heng v Public Prosecutor is significant for practitioners because it illustrates how Singapore courts evaluate diminished responsibility and provocation in a structured, evidence-sensitive manner. For diminished responsibility, the case reinforces that expert psychiatric evidence is crucial but not determinative. Courts will examine whether the factual basis for the expert’s conclusions is properly established and whether the accused’s conduct supports or undermines the claimed mental impairment. This is particularly important in cases where the defence relies on the accused’s self-reporting of symptoms.

For provocation, the case demonstrates that the statutory exception is not a general “loss of temper” defence. The court will assess whether the provocation is grave and sudden and whether the accused’s reaction is consistent with a genuine loss of self-control. Conduct that suggests deliberation, concealment, or post-offence planning may weigh heavily against the provocation narrative.

Finally, the constitutional dimension is a reminder that constitutional challenges to the Penal Code’s murder framework face a high bar. The Court of Appeal’s rejection of the separation of powers and Art 12(1) arguments confirms that the existing statutory structure for charging and adjudicating murder remains constitutionally sound. For law students and litigators, the case provides a useful example of how constitutional claims are treated alongside substantive criminal defences within the same appeal.

Legislation Referenced

• Penal Code (Cap 224, 2008 Rev Ed) — s 299
• Penal Code (Cap 224, 2008 Rev Ed) — s 300(a) (murder)
• Penal Code (Cap 224, 2008 Rev Ed) — s 300 (exceptions to murder, including Exception 1 and Exception 7)
• Constitution of the Republic of Singapore (1985 Rev Ed, 1999 Reprint) — Art 12(1)

Cases Cited

• Public Prosecutor v Teo Ghim Heng (Zhang Jinxing) [2021] SGHC 13
• Teo Ghim Heng v Public Prosecutor [2022] SGCA 10

Source Documents

• Original Judgment (PDF) — Singapore Law Watch
• Archived Copy (PDF) — Litt Law CDN

This article analyses [2022] SGCA 10 for legal research and educational purposes. It does not constitute legal advice. Readers should consult the full judgment for the Court's complete reasoning.